Compact airtype exhaust steam condenser system



y 25, 1955 K. w. WARTENBERG 3,185,213

COMPACT AIRTYPE EXHAUST STEAM CONDENSER SYSTEM Filed March 15, 1961 s Sheets-Sheet 1 May 25, 1965 K. W. WARTENBERG COMPACT AIRTYPE EXHAUST STEAM CONDENSER SYSTEM Filed March 15, 1961 3 Sheets-Sheet 2 y 1965 K. w. WARTENBERG COMPACT AIRTYPE EXHAUST STEAM CONDENSER SYSTEM 3 Sheets-Sheet 5 Filed March 15, 1961 United States Patent 3,185,213 COMPACT AIRTYPE EXHAUST STEAM CONDENSER SYSTEM Kurt Wilhelm Warteuberg, Kemmansweg 14, Kettwig (Ruhr), Germany Filed Mar. 15, 1961, Ser. No. 95,963 Ciaims priority, application Germany, Mar. 22, 1960, 1) 32,924 9 Claims. (El. 165-424) The present invention relates to devices for condensing a vapor by heat exchange with a cooling gas, and more particularly to those types of heat exchangers employing air to cool and condense the exhaust steam of a steam turbine which is fed to the heat exchanger at .a low absolute pressure. A conventional condenser system may comprise a plurality of heat exchangers called box condensers or cooling box-es.

Air-type condensers can be constructed only for a certain open-air temperature predetermined when the condenser is in the designing stage. This predetermined temperature is so chosen as to create a vacuum constituting the most economical maximum for the turbine or machine that is connected to the condenser. When the outdoor temperature is less than the predetermined temperature, the cooling surfaces of the condenser are too large, and complex circuits and devices are necessary in conventional condensers to balance this disadvantage. This regulation problem calls for particular attentionias the outdoor temperature; varying day and night, summer and winter, has the same effect as a varying load. When the outdoor temperature falls below the freezing point of water, that cooling area no longer required to create the vacuum within the condenser will cause icing which may cause the condenser to become inoperative or even destroyed. Owing to this danger of icing, the cooling areas or surfaces of the condenser have to be continuously adapted to the machine output depending on the outdoor temperature, for example, by regulating the air-blower power or by switching on a portion of the cooling surface area of the condenser. These measures are hard to maintain in a continuously operating plant and do not ensure perfect operation of the condenser.

In such condensers, the useful cooling surface will automatically decrease whenever the machine output rises, thus producing more waste steam. This effect is brought about by the increasing volume of the condensate covering a greater surface of the cooling condenser which portion of the surface becomes disabled to directly exchange heat. Another well-known disadvantage in conventional condensers is peculiar to those systems where the steam is ducted through sloping pipes exposed to a stream of cooling Here the drops of condensate forming at the uper end of a steam tube has to run down the whole length inside the tube to reach the condensate tank, all the time transferring its own heat to the tube along 'a path that is thus diverted from its intended task of cooling the steam; at temperatures below freezing point, these drops may freeze and gradually reduce the inner diameter of the tube especially because the cooling air is blown in a direction perpendicular to the tube centerlines, for this reason increasing the danger of icing. The fact that the useful cooling surface inside the tubes is reduced by the condensate settling on the tube walls has led designers to increase the dimensions of conventional air-type condensers to such a degree that they have become unprofitable as compared with condensers operating with cooling water.

These difiiculties with conventional air-type Wastesteam condensers are due to the limited possibility of favorably distributing the steam among the individual tubes so as to make best use of the available heat-exchange surface at varying load and to avoid extreme cooling and the danger 'of icing. As a result of this impossibility, the overall dimensions of conventional air condensers have been increased for a given volume of steam so that the efiiciency of these condensers is now rather low. On the other hand, the steadily increasing demand for power'and power plants presents problems in providing cooling water in areas where water for this purpose has become a scarce commodity and where the use of the surrounding air for cooling purposes is the only practicable solution. Similar considerations apply to thedncreased space requirements of the now oversized conventional air-type condensers.

It is therefore an object of the present invention to provide a condenser employing air to cool waste steam and having so compact a construction IBIS to substantially reduce the space required tor a conventional condenser.

Another object of this invention is to provide steamduoting means effectively reducing the loss of steam pressure, ensuring a high transfer of heat at the walls of the heat exchanger, preventing the condensate from asstuning an excessively low temperature, and efiiciently distributing the steam. V

A further object of this invention is to provide cooling means adapted to the high heat transfer at low pressure loss and adapted to thoroughly distribute the cooling air into the condenser.

Still another object of this invention is to provide means of quickly and efficiently conveying the condensate away from the heat-exchange surface of the condenser towards the condensate tank in such a way that the condensate, on its path to the tank, cannot come into contact with any part of the heat-exchange surface of the condenser.

Among the features believed to be characteristic of the present invention is a box condenser, preferably mounted in .a position sloping against the vertical, into which the steam to be condensed is ducted and evenly distributed so as to fill the box volume provided for the steam.

Another feature of this invention is a plurality of parallel tubes extending from one wall of the cooling box to the one opposite wall of the same box in a direction perpendicular to the longitudinal axis of the b x, both ends of the said tubes being open for air to flow thnough the tubes and to cool the steam surrounding the outer walls of the tubes inside the box.

Still another feature of the invention is a plurality of battles deflecting the condensate from the outer surfaces of the cooling tubes toward the condensate tank in such a way as to preclude contact between the condensate and the surfaces of cooling tubes on the path between the point of origination of the codensate and its tank.

A furtherfeature of this invention is an arrangement of fins longitudinally disposed inside the cooling tubes in such a manner that the cross-sectional density of the fins is the same in the vicinity of the centerline of the cooling tube and in the vicinity of the circumference of the crosssection. I i

The combination of these and other features described hereinafter brings about the desired results inasmuch as the bafiles are so arranged as to interfere with the normal downward movement of the condensate along the entire length of the tubes under the urging of gnavity and to quickly convey the condensate to its tank, thus liberating the cooling tubes from the layer of condensate and increasing the effective cooling surface; this in turn permits a relatively dense and compact arrangement of cooling tubes in the box which can be constructed of relatively low weight and small dimensions. Owing the the quick draining of the condensate from the cooling box of relatively small dimensions, the danger of icing has no chance to arise Whenever the outdoor temperature drops below the freezing point of water. The overall efficiency of the arrangement is enhanced by the steam being no longer ducted through pipes but being guided into the cooling Patented May 25, 1965 box to the surfaces of a relatively high number of cooling tubes having internal fins of a special cross sectionalv density.

In general, the invention provides a condenser operating with cooling air'independent of water supply and requiring a space that is not more than about 40 percent of a comparable conventional condenser of the same operating principle, the condenser being fully operative regardless of the varying machine load and regardless of the outdoor temperature. 7 7

Further details of the present invention pertain to the particular construction and arrangement of the individual parts thereof. It will be understood that various modifications maybe made therein audit is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

For a more detailed description of the invention, reference is made to the following specification \and the attached drawings wherein like reference numerals refer to the same parts throughout, and in which:

FIGURE l is a cross-sectional view of a cooling box of the present invention;

FIGURE 1A is an enlarged view of a detail of FIG- URE 1;

FIGURE 2 is a cross-sectional view of the cooling box elements of the invention taken substantially on the plane indicated by line II of FIG. 1;

FIGURE 3 is a cross-sectional view of the cooling box elements of the invention taken substantially on the plane indicated by line IIII of FIG. 2;

FIGURE 4 is a cross-sectional view of an air tube with internal fins;

FIGURE 5 is aside elevation showing an arrangement of a plurality of cooling boxes;

:FIGURE 6 is a side elevation of another arrangementof cooling boxes; and

FIGURE 7 is a side elevation of 'still another arrangement of cooling boxes. 7

A high-capacity condenser system is made up of a plurality of substantially identical cooling box units shown in FIG. 1, the number of cooling boxes varying with the amount of waste steam to be condensed. Each of the cooling boxes is connected to the exhaust main 5. The cooling box unit according to the invention substantially consists of a substantially closed container 1 of preferably rectangular cross-section in whose opposite walls 11 and 12 cooling or condensing tubes 2 are spaced at substantially like distances from one another. Through these cooling tubes, air passes under pressure from 7 to 8, as indicated by the arrows. In a preferred embodiment, the waste steam is led from the exhaust main 5 to the distribution manifold 4 and from thence into the cooling box cavity throughout, that is to say, even into the collecting tank 9 in the bottom portion ofthe container -1.- 'Baffie plates 3 extend substantially longitudinally of the axis of the cooling box, that is, transversely of the cooling tubes and slope downwardly more steeply than the tubes. These baffles serve to immediately deflect the condensate from the vertically extending outer walls of the cooling tubes so that the condensate bypasses the remainder of the tube walls and is guided int-o a path leading to the tank 9 from where it is drained through discharge 6.

The distance between adjacent bafiles is selected according to the atmospheric conditions prevailing at the place of operation. That is to say, the distance is such that even in the case of low outside-air temperature the condensate is still possessed of its latent heat of liquid when having arrived at a bafiie. In this manner it is insured that the condensate. cannot freeze, even when the cooling surfaces should not accurately correspond to the actual load requirements.

Whether such a coling box is economical in operation, is primarily judged by the loss of air pressure in the cooling tubes. The condenser tubes are therefore provided with flared intake portions 16, as shown in enlarged viewin FIG. 1A, which intake portions serve to reduce the loss of pressure of theingoing air. These trumpet like members 16 are preferably made of plastic and are Weather-resistant. They can be easily fitted over the tubes 2 which,'for this purpose, slightly project from the box 1.

FIG. 2 is a cross-section taken substantially on the plane indicated by line I-I of FIG. 1, showing .tubes 2 and a bafile plate 3 which may for instance consist f suitable plastic material.

FIG. 3 shows, by way of example, an embodiment in which the portions 1310f the'bafile plate 3 surrounding the baffle openings for the tubes are bent outward of the plane of the plate 3 to form a hood shaped flap extending over the top portion of. each aperture in the plate 3 through which a tube 2 passes in a horizontal direction. The condensate is thereby caused to flow downwards along the baffles, without contacting the cooling tubes. This has the advantage thatthe effective cooling surface remains unaffected by the flow of the condensate. According to another embodiment, the edges of the bafile openings may be completely bent off so as to form sleeves or flanges about the cooling tubes.

FIG. 4 is a cross-sectional view of a simplified arrangement of a cooling tube with internal fins. According to this arrangement, the center of the tube interior is provided with fever fins than are arranged at the circumference of the tube, which arrangement results in a better flow of heat from the circumference of the tube to the center line thereof. This arrangement of fins has been found particularly advantageous in the present case, inasmuch as the pattern of the air stream is more uniform throughout the cross-section of the tube than in the case of. tubes provided with a greater number of center fins, in which case the velocity of flow would be reduced in the center regions of such tubes.

In FIGS. 5 through 7 a plurality of the above-described cooling boxes are grouped together to form dilferent condenser systems.

According to the embodiment shown in FIG. 5, the cooling air 7 is sucked in by the blower 10 through the cooling tubes 2, from thence it is forced out as warm air through the outlet 14. The waste steam is fed into the system through the exhaust main 5 which in this case is arranged below the inclined coolingboxes 1. In this embodiment, the waste steam enters the system at the extermities of the cooling boxes 1.

FIG. 6 shows a modification of the arrangement in FIG. 5 wherein the cooling air 7 is forced through the cooling boxes 1 by blower 10. Naturally this system could also include an outlet 14 which is to be disposed above the condensers to prevent the blower from sucking in warm air. In this embodiment, the waste steam enters the system on the sides and at the upper extremities of the condensers. Where the steam enters the cooling box at its side, as is also shown in FIG. 1,baffles 3 are arranged in such manner that the steam has free access to all cooling tubes.

A further embodiment is shown in FIG. 7 wherein the shape of the condensers is'somewhat different from that of the previously shown condensers In this embodiment, exhaust main 5 is connected to tank 9, and the steam enters the system through the latter and then passes through the connecting tubes to the cooling tubes, in opposite direction of the flow of the condensate, while air is forced to flow throughthe cooling tubes by means of blower 10, as in the case of FIG. 5, the pattern of, air flow being slightly difierent from that used in the foregoing embodiments.

Having thus fully disclosed my invention, what I claim 1. A device for condensing a vapor by heat exchange with. a cooling gas comprising, in combination:

(a) a container enclosing a cavity therein;

(b) feeding means for feeding a condensable vapor to said cavity;

(c) collecting means for collecting condensed liquid from said cavity in a bottom portion of said container;

(d) a condensing tube passing through a portion of said cavity above said bottom portion and having a vertically extending outer wall in said cavity;

(2) pressure means for passing a cooling gas through said tube, whereby said vapor is condensed to liquid on a portion of said wall and said liquid is urged by gravity to flow downward along the remainder of said wall; and

(f) bafile means on said Wall for deflecting said liquid from said remainder of said wall into a path leading to said collecting means and by-passing said remainder.

2. A device as set forth in claim 1, wherein said tube has an obliquely sloping axis, and said path slopes downward from said wall portion more steeply than the slope of said axis.

3. A device as set forth in claim 1, wherein said vapor is steam, said gas is air, and said liquid is water.

4. A device as set forth in claim 1, further comprising a plurality of fins, said tube having an axis, and said fins being arranged about said axis in said tube and extending axially therein so as to be substantially uniformly spaced from each other in a plane transverse of said axis.

5. A device as set forth in claim 1, wherein said container has two opposite walls, said tube passing through said opposite walls.

6. A device as set forth in claim 5, wherein said tube projects outward through one of said walls, the projecting portion of said tube being outwardly flared.

7. A device for condensing a vapor by heat exchange with a cooling gas comprising, in combination:

(a) a container enclosing a cavity therein;

(b) feeding means for feeding a condensable vapor to said cavity;

(c) collecting means for collecting condensed liquid from said cavity in a bottom portion of said container; (d) a plurality of condensing tubes passing through a portion of said cavity above said bottom portion, 5 each tube being spaced from the other tubes and having a vertically extending outer wall portion in said cavity;

(a) pressure means for passing a cooling gas through said tubes, whereby said vapor is condensed to liquid on respective portions of said Walls, and the liquid is urged by gravity to flow downward along the remainders of said respective walls; and

(f) bafile means on said walls for deflecting the condensed liquid from said remainders of said walls into a path leading to said collecting means and bypassing said remainders.

8. A device as set :forth in claim 7, wherein said baffle means include a vertically extending plate member formed with a plurality of apertures therein, said tubes passing through respective ones of said apertures in a horizontally extending direction.

9. A device as set forth in claim 7, wherein said feeding means include a plurality of vertically spaced inlet means on said container.

References Cited by the Examiner UNITED STATES PATENTS 1,380,460 7/21 Bancel 165-144 X 1,644,520 10/27 Hagerman 165-122 2,107,478 2/38 Happel 165-127 3,039,744 6/62 Jacobs et a1 165-1'80 X 3,045,981 7/ 62 Hendrickson 165-178 X FOREIGN PATENTS 700,872 12/53 Great Britain.

CHARLES SUKALO, Primary Examiner.

HERBERT L. MARTIN, Examiner. 

1. A DEVICE FOR CONDENSING A VAPOR BY HEAT EXCHANGE WITH A COOLING GAS COMPRISING, IN COMBINATION: (A) A CONTAINER ENCLOSING A CAVITY THEREIN; (B) FEEDING MEANS FOR FEEDING A CONDENSABLE VAPOR TO SAID CAVITY; (C) COLLECTING MEANS FOR COLLECTING CONDENSED LIQUID FROM SAID CAVITY IN A BOTTOM PORTION OF SAID CONTAINER; (D) A CONDENSING TUBE PASSING THROUGH A PORTION OF SAID CAVITY ABOVE SAID BOTTOM PORTION AND HAVING A VERTICALLY EXTENDING OUTER WALL IN SAID CAVITY; (E) PRESSURE MEANS FOR PASSING A COOLING GAS THROUGH SAID TUBE, WHEREBY SAID VAPOR IS CONDENSED TO LIQUID ON A PORTION OF SAID WALL AND SAID LIQUID IS URGED BY GRAVITY TO FLOW DOWNWARD ALONG THE REMAINDER OF SAID WALL; AND 